We generally hear four arguments. First, if the Taliban returns to power, Afghanistan will again be a haven for terrorist groups. Second, if the Taliban takes over, Afghanistan will again become a human rights nightmare. Third, a perceived defeat of the United States in Afghanistan would be a blow to U.S. prestige everywhere and would embolden radicals. Fourth, an Afghanistan under Taliban control would be used by extremists as a sanctuary from which to destabilize Pakistan.

None of these assumptions is as strong as proponents maintain. Afghanistan certainly matters -- the question is how much.

Al-Qaeda does not require Afghan real estate to constitute a regional or global threat. Terrorists gravitate to areas of least resistance; if they cannot use Afghanistan, they will use countries such as Yemen or Somalia, as in fact they already are. No doubt, the human rights situation would grow worse under Taliban rule, but helping Afghan girls get an education, no matter how laudable, is not a goal that justifies an enormous U.S. military commitment. And yes, the taking of Kabul by the Taliban would become part of the radicals' narrative, but the United States fared well in Asia after the fall of South Vietnam, and less than a decade after an ignominious withdrawal from Beirut, the United States amassed the international coalition that ousted Saddam Hussein from Kuwait. There are and always will be opportunities to demonstrate the effectiveness of U.S. power.

The one issue that should be at the core of the United States' Afghan strategy is Pakistan. It is there, not Afghanistan, where the United States has vital national interests. These stem from Pakistan's dozens of nuclear weapons, the presence on its soil of the world's most dangerous terrorists and the potential for a clash with India that could escalate to a nuclear confrontation.

The United States is doing a great deal in Afghanistan -- and is considering doing more -- because it sees the effort as essential to protecting Pakistan. But this logic is somewhat bizarre. Certainly, allowing the Taliban and al-Qaeda to reestablish a sanctuary in Afghanistan would make it harder to defeat them in Pakistan. But the Taliban and al-Qaeda already have a sanctuary -- in Pakistan itself.

It is the government of Pakistan that is tolerating the very groups that the United States is fighting in Afghanistan in the name of Pakistan's stability. It is worth noting, too, that Pakistani officials are not asking the United States to commit additional troops to Afghanistan, in large part because many Pakistanis view Afghanistan as one of several fronts in their struggle against India and see the Taliban as foot soldiers in that contest. Pakistan's future will be determined far more by its willingness and ability to meet internal challenges than by anything that emanates from across its border.

All of this argues that U.S. interests in Afghanistan are less than fundamental, rendering the conflict not a war of necessity but a war of choice. As befitting a war of choice, there are options available to the United States that fall between sending tens of thousands of additional troops, as Gen. Stanley McChrystal is reportedly requesting, and simply abandoning the country to its fate -- options in which the costs and benefits are consistent with what is at stake.

Recent news accounts suggest that President Obama is seeking precisely such a middle ground. What might it look like? The United States would maintain for now roughly its current number of troops in Afghanistan, although the balance between trainers and warfighters would shift toward the former. It would train the Afghan National Army and police force at an accelerated pace. Just as important, the United States would increase its arming and training of regional and local army and police forces loyal to selected local leaders. This would be akin to the successful strategy in the Sunni areas of Iraq and would reflect the Afghan reality of a weak center coexisting with strong warlords. Over time, these steps would allow for a gradual reduction in U.S. forces.

The United States would spend money liberally to redirect the loyalty of individuals and groups tied to the Taliban. Many are Pashtun nationalists more than anything else; there is no reason to assume that all Taliban members are implacably opposed to the United States or are committed to reestablishing the intimate ties with al-Qaeda that they had a decade ago.

The United States would increase aid to the government in Kabul only if President Hamid Karzai agrees to form a broad-based coalition government. Without this, he will not have the legitimacy to lead -- or to be an effective partner for the United States -- given the fraud that characterized the recent national election.

U.S. and Afghan armed forces would be concentrated in the capital and major population areas. Drone attacks would be ordered when high-value targets were identified and the prospects for collateral damage were slight. A standing high-level diplomatic group involving Afghanistan's immediate neighbors (including Iran) and others with a stake in the country's future (the United States, Russia, India, Europe) would meet regularly to coordinate policy.

Aid to Pakistan would rise dramatically. It makes no sense that the United States now invests $20, or by some estimates $30, in Afghanistan for every $1 it spends in Pakistan. Pakistani textiles would gain easier access to the U.S. market. And the United States would expend greater diplomatic effort to reduce Indo-Pakistani tensions.

Would this strategy work? No, if by "work" one envisions Afghanistan and Pakistan as peaceful, prosperous and responsible states living side by side. But our goals need to be more modest. What the United States and the world should seek is a Pakistan that remains intact, and exercises tight control over its nuclear weapons and considerable if not total control over terrorists within its borders. In Afghanistan, the near-term goal should be the building of a central government that, together with various local leaders, can limit the presence of terrorists. Anyone who thinks this is not bold enough should keep in mind that even modest objectives tend to be ambitious in this part of the world.

It is an error to equate the depth of U.S. commitment to the level of combat troops, as greater numbers and activity will not necessarily lead to results commensurate with the cost. Aid must be generous but conditioned on commitments and performance, and military and economic costs must be kept in check. And it is essential to remember that Afghanistan is but one of the strategic challenges facing the United States. Resources must be husbanded for Iran, Iraq and North Korea, to name just a few. McChrystal has the responsibility to argue for the resources he believes are needed to fulfill his mission in Afghanistan; the president, responsible for protecting U.S. interests worldwide, has no such luxury.

It has become fashionable to deride a middle way on tough policy challenges. Those in the center are deemed guilty of the sort of incrementalism that got us in trouble in Vietnam, indecisiveness or worse. In Afghanistan, however, it may be that a middle way between surging and leaving is the best -- or more accurately, the least bad -- option.

Richard N. Haass is the president of the Council on Foreign Relations and the author of "War of Necessity, War of Choice: A Memoir of Two Iraq Wars."

***

While Haass calls for the Obama administration to take a middle road in Afghanistan, Rajiv Chandrasekaran reports on the perils of that path in "Go All-In, or Fold," Outlook's Sept. 27 cover story. And Peter W. Galbraith, formerly the second-ranking U.N. official in Afghanistan,blasts the United Nationsfor not averting fraud in the country's recent presidential vote.